There is a continuing demand for strong magnetic fields of thousands of gauss with large gradients of thousands of gauss per centimeter for mechanical device applications such as activators, mechanical bearings and magnetic separators, as well as electromagnetic applications including partial beam experiments, microwave radiation sources, mm-wave radiation sources, free electron lasers and so on. A major difficulty in magnetic design is the lack of the free electronic charge used in electrical designs. In magnetics, every magnetic positive charge, e.g. north magnetic pole, is always accompanied by an equal and opposite negative charge in the south magnetic pole. Whenever a specific charge distribution is needed to configure a desired magnetic field, the negative counterparts of the required charges need to be rendered minimally deleterious to the desired magnetic field. Further, prior art techniques for producing a magnetic field gradient such as producing a field-taper normal to the direction of the field lines, an axial taper in the remanences of the magic cylinders, or a longitudinal taper, are considered inadequate and ineffective because they are complex, expensive and time-consuming. Prior art magnetic structures are unable to effectively minimize the deleterious effects of the unwanted counterparts of required charges. Thus, there has been a long-felt need for simple and inexpensive magnetic field gradient sources that produce a strong volume charge density using layered structures that can cancel unwanted surface charges. This invention's magnetic field gradient source structures can produce the long-sought volume charge density in a number of inexpensive and relatively simple layered arrangements that cancel unwanted surface charges, without suffering from the disadvantages, limitations and shortcomings of prior art magnetic structures.
The magnetic structures of the present invention overcome the shortcomings and limitations of minimizing unwanted negative charges with a layered, or laminated, arrangement of magnets configured so that the unwanted negative charges are mutually cancelled by other parts of the structure. The field gradient sources of the present invention comprise a series of stacked magnetic laminae that are magnetically oriented perpendicular to their planes in a number of configurations. The magnetic structure of the present invention makes it possible to fulfill the long-felt need for a simple and inexpensive way of providing a field gradient source that does not suffer from the disadvantages, limitations and shortcomings of complex, expensive and time-consuming prior art high magnetic field devices. As used herein, the terms “lamina” and “laminae” are defined as any thin plate, sheet or layer.